Novel superhydrophilic nanofiber membranes with high flux and durability enable multifunctional oil-water separation

Despite the widespread interest in membrane technology for the separation of oily wastewaters, generation of discarded membranes and single-function pose huge challenges for eco-friendly and green separation. Herein, we presented an on-demand biodegradable, multifunctional and superhydrophilic nanofiber membrane composed by polylactic acid (PLA) and novel metal-polyphenol networks (MPNs). The novel MPNs were formed by stacking ellagic acid (EA) and Fe3+, which turned hydrophobic PLA nanofiber membranes (WCA = 118 degrees) into superhydrophilic (WCA = 0 degrees). We carried out several studies which have demonstrated that the designed EA-Fe-PLA/ PVP nanofiber membranes exhibited high separation efficiency under gravity alone, the separation efficiency exceeded 99 %, and the oil-in-water emulsions and oil/water mixtures flux of membranes were 4120 and 50,360 L.m-2.h-1, respectively. The separation performance far exceedingly recent reported advanced oil-water separation membranes. Meanwhile, the EA-Fe-PLA/PVP nanofiber membranes demonstrated outstanding selfcleaning, excellent photocatalytic and distinguished biodegradation property. Additionally, the density functional theory (DFT) indicated that the strong interaction between EA and Fe3+, enhanced significantly cycling stability and chemical stability of membranes, which were essential in daily separation applications, especially where durability and reliability were required.